/*
 * Copyright � 2002-2011 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using System.ComponentModel;
using System.Globalization;
using System.Reflection;
using System.Resources;
using Spring.Core.TypeResolution;
using Spring.Util;

namespace Spring.Core.TypeConversion;

/// <summary>
/// Converts a two part string, (resource name, assembly name)
/// to a ResourceManager instance.
/// </summary>
public class ResourceManagerConverter : TypeConverter
{
    /// <summary>
    /// This constant represents the name of the folder/assembly containing global resources.
    /// </summary>
    public static readonly string APP_GLOBALRESOURCES_ASSEMBLYNAME = "App_GlobalResources";

    /// <summary>
    /// Creates a new instance of the
    /// <see cref="Spring.Core.TypeConversion.ResourceManagerConverter"/> class.
    /// </summary>
    public ResourceManagerConverter()
    {
    }

    /// <summary>
    /// Returns whether this converter can convert an object of one
    /// <see cref="System.Type"/> to a
    /// <see cref="System.Resources.ResourceManager"/>
    /// </summary>
    /// <remarks>
    /// <p>
    /// Currently only supports conversion from a
    /// <see cref="System.String"/> instance.
    /// </p>
    /// </remarks>
    /// <param name="context">
    /// A <see cref="System.ComponentModel.ITypeDescriptorContext"/>
    /// that provides a format context.
    /// </param>
    /// <param name="sourceType">
    /// A <see cref="System.Type"/> that represents the
    /// <see cref="System.Type"/> you want to convert from.
    /// </param>
    /// <returns>True if the conversion is possible.</returns>
    public override bool CanConvertFrom(
        ITypeDescriptorContext context,
        Type sourceType)
    {
        if (sourceType == typeof(string))
        {
            return true;
        }

        return base.CanConvertFrom(context, sourceType);
    }

    /// <summary>
    /// Convert from a string value to a
    /// <see cref="System.Resources.ResourceManager"/> instance.
    /// </summary>
    /// <param name="context">
    /// A <see cref="System.ComponentModel.ITypeDescriptorContext"/>
    /// that provides a format context.
    /// </param>
    /// <param name="culture">
    /// The <see cref="System.Globalization.CultureInfo"/> to use
    /// as the current culture. 
    /// </param>
    /// <param name="value">
    /// The value that is to be converted.
    /// </param>
    /// <returns>
    /// A <see cref="System.Resources.ResourceManager"/>
    /// if successful. 
    /// </returns>
    /// <exception cref="ArgumentException">If the specified <paramref name="value"/> does not denote a valid resource</exception>
    public override object ConvertFrom(
        ITypeDescriptorContext context,
        CultureInfo culture, object value)
    {
        if (value is string)
        {
            // convert incoming string into ResourceManager...
            string[] resourceManagerDescription = StringUtils.DelimitedListToStringArray((string) value, ",");
            if (resourceManagerDescription.Length != 2)
            {
                throw new ArgumentException("The string to specify a ResourceManager must be a comma delimited list of length two.  i.e. resourcename, assembly parial name.");
            }

            string resourceName = resourceManagerDescription[0].Trim();
            if (resourceName != null && resourceName.Length == 0)
            {
                throw new ArgumentException("Empty value set for the resource name in ResourceManager string.");
            }

            string assemblyName = resourceManagerDescription[1].Trim();
            if (assemblyName != null && assemblyName.Length == 0)
            {
                throw new ArgumentException("Empty value set for the assembly name in ResourceManager string.");
            }

            if (assemblyName == APP_GLOBALRESOURCES_ASSEMBLYNAME)
            {
                try
                {
                    Type globalResourcesType = TypeResolutionUtils.ResolveType(resourceName);
                    // look both, NonPublic and Public properties (SPRNET-861)
                    PropertyInfo resourceManagerProperty = globalResourcesType.GetProperty("ResourceManager", BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Static);
                    return (ResourceManager) resourceManagerProperty.GetValue(globalResourcesType, null);
                }
                catch (TypeLoadException ex)
                {
                    throw new ArgumentException("Could not load resources '{0}'", resourceName, ex);
                }
            }

            Assembly ass = Assembly.LoadWithPartialName(assemblyName);
            if (ass == null)
            {
                throw new ArgumentException("Could not find assembly with name = '" + assemblyName + "'.");
            }

            return new ResourceManager(resourceName, ass);
        }

        return base.ConvertFrom(context, culture, value);
    }
}